Pressure responsive volume control for electrical instruments



May 9, 1967 3,318,991

PRESSURE RESPONSIVE VOLUME CONTROL FOR ELECTRICAL INSTRUMENTS J. c. COOKERLY ET AL Filed March 6, 1964 I Voum: CONTROL Tmmsouczn FIG. I.

VI $2 m N H k w m wm A United States Patent 3,318,991 PRESSURE RESPONSIVE VOLUME CONTROL FOR ELECTRICAL INSTRUMENTS Jack C. Cookerly, 7566 Atoll Ave., North Hollywood,

Calif. 91605, and George R. Hall, 13613 Huston St.,

Sherman Oaks, Calif. 91403 Filed Mar. 6, 1964, Ser. No. 349,927 3 Claims. (Cl. 84--1.1)

ABSTRACT OF THE DISCLOSURE This disclosure relates to a pressure transducing device responsive to variations of air pressure within the bellows of an accordion for controlling the gain of an amplifier. Tone signals are generated in response to playing of the accordion and passed through this amplifier. The tone signals are thus changed in amplitude or intensity in accordance with the pressure in the bellows of the accordion which pressure in turn is determined by the players attack on the bellows. Thus there is provided a variation in volume in accordance with the players intentions by means of the pressure transducing device,

This invention relates generally to musical instruments and more particularly to a novel pressure responsive volume control for electrical instruments in which tones are initiated by air flow.

In instruments requiring air flow for the generation of tones such as accordions, by way of example, the volume of the output sound is normally controlled by the pressuring causing the air flow. Thus, in the case of an accordion, the force supplied by the player towards the collapsing or. expanding of the accordion bellows determines the volume of the output notes.

In the case of electrical accordions, the tones are initiated by the accordion keys which function to close electrical switches to provide electrical signals. These electrical signals constitute the outputs of various oscillators of frequencies corresponding to the desired tones. Usually, the tonal outputs from the various tone generating circuits are all of constant amplitude. Accordingly, the player of an electrical accordion may attack the instrument in a conventional fashion but the output volume will be at a constant level, as determined by the control of an output amplifier. There is no means for varying the volume of individual notes or phrases within the composition being played in accordance with the action of the player on the instrument.

With the foregoing considerationsin mind, it is accordingly a primary object of this invention to provide an improved electrical instrument in which output tones provided from electrically generated signals are varied in volume in exactly the same manner as intended by a player of the instrument.

More particularly, it is an object to provide a pressure responsive volume control for an electrical instrument such as an accordion in which the output volume will vary directly with the pressure of air generated in the belows as determined by the musician to the end that the finally sounded notes will more realistically follow the volume variations desired by the musician.

Briefly, these and many other objects and advantages of this invention are attained by providing an auxiliary transducer means responsive to pressure variations in the air pressure generated by the musician in playing the instrument. This auxiliary transducer provides a control signal which in turn is fed into the electrical circuitry of the output portion of the instrument to vary the volume continuously in accordance with variations in the control "ice signal. Since these latter variations in turn depend upon the pressure of air as exists, for example, in an accordion bellows, the volume of each individual output tone or tones will vary in the same manner as though the instrument were played merely as a conventional acoustic type instrument.

A better understanding of the invention will be had by now referring to the accompanying drawings of one embodiment thereof in which:

FIGURE 1 illustrates partly in block form and partly schematically an air flow control instrument such as an accordion incorporating the novel pressure responsive volume control of this invention; and,

FIGURE 2 is an enlarged elevational view partly in cross-section of the volume control transducer portion of the system illustrated in FIGURE 1.

Referring first to FIGURE 1, there is illustrated at A an accordion having a bellows 10 and various electrical leads 11 connected to notes on a keyboard 12 and chord buttons on a chord board 13. Normally, in an electrical accordion, operation of the notes and chord buttons serve to switch on suitable tone generating circuits 14. The output electrical signals from the tone circuits 14 are all of constant amplitude and are then passed through an audio amplifier 15 to a speaker 16.

With respect to the foregoing, it should be understood that the operation of the notes and chord buttons functions only to close or open switches to trigger signals from these oscillators or to pass signals from the oscillators to the output circuits. Thus, when the player of the accordion intends that a note have considerable volume, his action on the bellows 10 has no eifect in varying the volume of the note.

In accordance with the instant invention, the foregoing problem is overcome by providing an auxiliary volume control means. This structure takes the form of a volume control transducer normally located beneath the keyboard 12 but shown in exploded view at 17, extended from the accordion A for purposes of illustration. Two output leads 18 and 19 extend from the volume control transducer 17 and may be passed through the same cable incorporating the various individual switch leads 11. However, these output leads bypass the tone generating control circuits 14 and as shown are connected directly to a volume control means such as the amplifier 15.

The volume control transducer 17 of FIGURE 1 is responsive to pressure variations in the bellows 10. Thus, when the pressure is increased in the bellows 10, an electrical control signal provided by the combination of the transducer 17 and amplifier 15 is caused to vary in amplitude to control the amplification of the amplifier 15. As a result, each output tone from the speaker 16 will have a volume directly proportional to the pressure of air in the bellows 10 in turn generated by the musician so that the sound of the electrical instrument will follow in volume in accordance with the musicians attack on the instrument.

One suitable type of pressure transducer which may be incorporated in the casing 17, is illustrated in FIG- URE 2. As shown, this transducer includes a bellows structure 20 hinged at 21 to the left internal side of the casing 17 for up and down movement in response to variations in the air pressure in the bellows 20. The bellows 20 is held in a neutral position by a leaf-type spring 22. Variations in the internal pressure of the bellows 20 are efiected by a connecting airtube 23 passing to the main bellows 10 of the accordion. Thus, when an increase or decrease in air pressure in the main bellows 10 occurs, the auxiliary bellows 20 will correspondingly be caused to expand or contract.

To the extreme right end of the bellows 20 there is secured a fixture 24 supporting a light source in the form of a neon lamp 25. This light source will thus move up and down depending upon pressure variations within the bellows 20. Cooperating with the neon light source 25 is a stationary mask 26 having a central o.pen ing 27 therein. Positioned behind the opening 27 is a photosensitive resistance cell 28 having output leads connecting to the leads 18 and 19 extending from the casing 17.

The fixture 24, neon light 25, stationary mask 26 with opening 27, and photosensitive resistance 28 constitute a variable resistance means responsive to movement of the pressure responsive bellows 20 for providing the desired control signal.

To control volume by means of the transducer described in FIGURE 2, the leads 18 and 19 are connected in series with the bias control resistance within the amplifier 15 so that the resistance of the cell 28 is directly in series with the bias control resistance. The resistance of the cell 28 in turn is a function of the amount of light falling on the cell and will thus vary when there is a variation in the light received by the cell. This variation in resistance will result in an overall variation in the bias of the amplifier 15 to thereby change its gain. Thus, a control signal may be considered as being derived from across the variable photosensitive resistance 28.

The operation of the volume control circuit will be evident from the foregoing description. If the player exerts considerable pressure on the bellows 10, the increased pressure in the auxiliary bellows 20 will move the bellows in an upward direction thereby decreasing the amount of light passing through the stationary opening 27 and the mask 26 to the cell 28. A decrease of the amount of light on the cell 28 will cause its resistance to increase thereby increasing the overall series resistance in the bias control circuit amplifier 15. This increase in the bias resistance will result in an increase in the gain of the amplifier to increase the volume of the notes sounded from the speaker 16.

If the pressure within the principal bellows of the accordion is decreased as when the musician plays softly, the auxiliary bellows 20 will tend to return to its neutral position as controlled by the spring 22 so that maximum light will then be received through the now centered opening 27 in the mask 26. When the maximum light falls on the cell, its resistance decreases so that the overall bias control resistance is decreased and the gain of the amplifier correspondingly is decreased.

It will be evident from the foregoing that the output volume of each and every note played by the musician will be under control of the musician himself. There is thus provided proper tonal qualities for the notes in the particular selection being played.

What is claimed is:

1. A pressure responsive volume control for an electrical instrument in which keys for playing notes normally generated by air flow are used to generate electrical signals of constant amplitude, comprising, in combination: transducer means connected to said instrument and responsive to pressure variations in said air flow to provide a control signal; and means connected to receive said electrical signals of constant amplitude and said control signal and responsive to said control signal to vary the amplitude of said electrical signals in accordance with variations in said control signal.

2. The subject matter of claim 1, in which said electrical instrument comprises an accordion, said transducer means including: a pressure responsive member connected to the bellows of said accordion for actuation by changes in pressure occurring within said bellows; and a resistance means responsive to actuation of said pressure responsive member to change its value, said control signal being derived from a signal applied across said resistance means.

3. The subject matter of claim 2, in which said re sistance means includes a light source connected to said pressure responsive member for movement therewith; a

. stationary mask having an opening through which a given amount of light passes depending on the relative positions of said light source and mask; and a photo-sensitive resistance cell positioned to receive light through said opening in said mask, the resistance of said cell being a function of the .amount of .light falling thereon.

No references cited.

ARTHUR GAUSS, Primary Examiner.

J. BUSCH, Assistant Examiner. 

1. A PRESSURE RESPONSIVE VOLUME CONTROL FOR AN ELECTRICAL INSTRUMENT IN WHICH KEYS FOR PLAYING NOTES NORMALLY GENERATED BY AIR FLOW ARE USED TO GENERATE ELECTRICAL SIGNALS OF CONSTANT AMPLITUDE, COMPRISING, IN COMBINATION: TRANSDUCER MEANS CONNECTED TO SAID INSTRUMENT AND RESPONSIVE TO PRESSURE VARIATIONS IN SAID AIR FLOW TO PROVIDE A CONTROL SIGNAL; AND MEANS CONNECTED TO RECEIVE SAID ELECTRICAL SIGNALS OF CONSTANT AMPLITUDE AND SAID CONTROL SIGNAL AND RESPONSIVE TO SAID CONTROL SIGNAL TO VARY THE AMPLITUDE OF SAID ELECTRICAL SIGNALS IN ACCORDANCE WITH VARIATIONS IN SAID CONTROL SIGNAL. 